According to theoretical and experimental studies, the oil recovery of a formation under thermal action depends mainly on the temperature of reservoir heating. In turn, the temperature reservoir heating depends on the volume of steam injection per unit of the heated volume and the thermal efficiency of the process. Also, the geological and technological parameters of the reservoir exert no less significant influence on the degree of production of reserves. Thus, the quantitative determination of the influence degree of these parameters on the oil recovery at different stages of thermal development is an extremely important task. Its solution will allow to effectively control the process of thermal impact in the conditions of the Yaregskoye field.
At present, reserves of Yaregskoye field are developing by thermal methods. During operations a number of problems arise, one of them is the determination of the optimal technological regimes of thermal impact on the formation at each stage of development. Under optimal regimes we understand rates and volumes of steam injection necessary to achieve the maximum oil recovery ratio and minimum steam oil ratio.
Based on the results of physical and mathematical modeling and core research we conducted studies to determine the optimal strategy for injecting steam. The results of laboratory and numerical experiments show that the greatest oil recovery can be achieved with a comprehensive understanding of the mechanism of injection of the heating agent and optimization of this process. Based on the numerical experiments on oil displacement, a clear dependence was established with the results of laboratory core studies. So in order to achieve optimal values, it is required to introduce the maximum possible amount of energy into the formation in the first stage and subsequently gradually reduce the vapor injection pressure to prevent the vapor from breaking through.
